given a positionable stream, guess its encoding (by reading the
first few lines, looking for a string with an encoding hint,
and return an appropriate encoded string, which does the decoding
on the fly. Used mostly to read UTF8 files (source code)

(comment from inherited method)this should return the class of which an instance is
returned by the #contents method. Here, Array is returned,
since the abstract Stream-class has no idea of the underlying
collection class.
It is redefined in some subclasses - for example, to return String.

(comment from inherited method)return the next element of the stream without advancing (i.e.
the following send of next will return this element again.)
- we do not know here how to do it, it must be redefined in subclass